720 THE CRIXOIDEA CAMEEATA OF NORTH A51EEICA. 



Remarks. — This genus bears the same relation to Platycrlnus that Slega- 

 nocrinus does to Adinocrinus. In both groups the rays branch in their free 

 state ; but while in Plati/criniis and Actinocrinus the covering plates are 

 movable from the costals up, they are in sutural contact in Eucladocrinus and 

 Stegamcrinus to the end of the appendages, and the latter practically form 

 extensions of the calyx. 



In Part II. of the Eevision we placed under this genus only those species 

 in which the arm trunks extend to the full height of the crowu, and in which 

 the arms are given off singly from opposite sides. This excluded such 

 forms as " Platycriniis" prcenuntius and " Platycrinus" tuberosus, which have 

 unquestionably the characteristics of Eucladocrinus, but less completely 

 developed. 



Eucladocrinus millebrachiatus w. and Sp. 

 Plate LXXIII. Fig. 1, and Plate LXXIV. Figs. 2, 3, 4, 5, 6, 7, 8, 9. 



1S78. W. and Sp. ; Proceed. Acad. Nat. Sci. Phila., p. 215, aud 1S81, Revisiou, Part II., p. 77 (Proceed. 

 Acad. Nat. Sci. Pbila., p. 2.51). 



A rather large species, resembling Platycrinus glyptus in the form of the 

 calyx and style of ornamentation. Dorsal cup bell-shaped, a little higher 

 than wide, the rays extended outward and forming above the distichals ten 

 ponderous tubular appendages, two to the ray, which, curving downward, 

 expose the ventral surface, and give off simple arms to nearly the full height 

 of the crown. Ventral disk very short and flattened on the top. Surface 

 of basals and radials marked by rows of small nodes and rugose ridges, 

 arranged parallel to the margins of the plates, and radiating to their angles. 



Basals forming a saucer-shaped dish, equal in height to one third the 

 length of the dorsal cup, truncated at the bottom, the middle portions de- 

 pressed to the width of the column; the interbasal sutures invisible. Eadials 

 longer than wide, very slightly increasing in width upward, a little gibbous 

 in the middle, and swelling toward the facets ; the edges of the plates not 

 beveled, and the interradial suture lines ill-defined. Facets large, semi- 

 circular, facing almost horizontally outward, occupying two thirds the width 

 of the plates and nearly one third their height; the surface slightly pitted 

 in the middle. Costals very short but wide, filling the entire sm-face of the 

 facets, and abutting against the lower end of the interradial plates; the 

 distal faces, although the plates are axillary, almost parallel with the proxi- 



